As a technique that allows a program to be run on nodes, such as routers or switches, arranged on a network, there is known an active network (see Non-Patent Document 1). There is disclosed in Patent Document 1 an active network provided with a signaling control unit which, by advance signaling, arrays an active code in a network's node.
In Patent Document 2, there is disclosed an optical communication system in which an integrated service class may be applied in different packet rings for packet flows being forwarded through the different packet rings. A node device of the optical communication system extracts the inter-ring service class information contained in the inter-ring header information appended to a packet incoming from another packet ring. Based upon the so extracted inter-ring service class information, the node device refers to a table that has recorded the relationship of correspondence between the inter-ring service class and the intra-ring service class, as set between the packet rings, in order to decide on the intra-ring service class to be set for the incoming packet. The node device appends the intra-ring header information, inclusive of the so determined intra-ring service class information, to the incoming packet.
On the other hand, a technique termed “source routing” is known as a system that exercises route control in say an IP network. As set out in Non-Patent Document 2, the source routing is implemented by specifying an IP address of a relaying router.
In these days, a technique termed “OpenFlow” has been proposed, as indicated in Non-Patent Document 3. In OpenFlow, communication is grasped as end-to-end flow, and route control, restoration from malfunctions, load distribution and optimization are accomplished on the flow basis. An OpenFlow switch, operating as a forwarding node, includes a secure channel for communication with an OpenFlow controller, and is run in accordance with a flow table to which a command for addition or rewrite is given from time to time from an OpenFlow controller. In the flow table, a set of rules (FlowKey), matched to a packet header, actions (Actions) that defines contents of the processing operation and the flow statistic Information (Stats) are defined from one flow to another (see FIG. 6).
FIG. 29 illustrates action names and contents of actions defined in Non-Patent Document 4. OUTPUT is an action for outputting to a specified port (interface). SET_VLAN_VID down to SET_TP_DST are actions that modify the fields of a packet header.
For example, the OpenFlow switch retrieves (looks up), on receipt of a first packet, an entry having a rule (FlowKey) matched to the header information of the received packet from the flow table. If, as a result of retrieval (lookup), an entry that fits with the packet received is found, the OpenFlow switch performs the contents of the processing operation, as set out in an action field of the entry, on the packet received. If, conversely, an entry that fits with the packet received is not found, the OpenFlow switch forwards the received packet over a secure channel to the OpenFlow controller to request the OpenFlow controller to decide on a route for the received packet based upon the source as well as the destination of forwarding of the received packet. The OpenFlow switch then receives a flow entry that implements the communication, while updating the flow table.    Patent Document 1:    JP Patent Kohyo Publication No. JP-P2006-513671A    Patent Document 2:    JP-Patent Kokai Publication No. JP-P2008-236652A